Evaluate the following expression when $a = 5$ and $b = 3$. $10$ $a$ $ + 7$ $b$ $ - 10$
Solution: Substitute $5$ for ${a}$ and $3$ for ${b}$ $ = 10{(5)} + 7{(3)} - 10 $ $ = 50 + 21 - 10 $ $ = 61$